export default {
   namespaced:true, //开启命名空间
   state:() =>({
      //购物车数组，用来存储购物车中每个商品信息对象
      //每个商品的信息对象，都包含如下 6 个属性
      //{goods_id, goods_name, goods_price, goods_count, goods_small_logo, goods_state}  
      cart :JSON.parse(uni.getStorageSync('cart')||'[]')
   }),
   
   mutations : {
      addToCart(state,goods){
       const findResult = state.cart.find(x => x.goods_id === goods.goods_id)     
        if (!findResult) {
          state.cart.push(goods)
        } else {   
          findResult.goods_count++
        }
        this.commit('m_cart/saveToStorage')
      },
      saveToStorage(state){
         uni.setStorageSync('cart',JSON.stringify(state.cart))
      },
      updateGoodsState(state,goods){
        const findResult = state.cart.find(x => x.goods_id === goods.goods_id)
        if(findResult){
          findResult.goods_state = goods.goods_state
          this.commit('m_cart/saveToStorage')
        }
      },
      updateGoodsCount(state,goods){
       const findResult = state.cart.find(x => x.goods_id === goods.goods_id)
        if(findResult){
           findResult.goods_count = goods.goods_count
           this.commit('m_cart/saveToStorage')
        }
      },
      removeGoodsById(state,goods_id){
        state.cart = state.cart.filter(x => x.goods_id !== goods_id)
         this.commit('m_cart/saveToStorage')
      },
      //更新购物车商品状态
      updateAllGoodsState(state,newState){
        state.cart.forEach(x => x.goods_state = newState)
        this.commit('m_cart/saveToStorage')
      }
   },
   getters : {
     //购物车中所有商品的数量
     total(state) {
       //let c = 0
       //state.cart.forEach(x => c+= x.goods_count)
       //return c
      return state.cart.reduce((total,item) =>  total += item.goods_count,0)
     },
     //购物车中已勾选的数量
     checkedCount(state){
       return state.cart.filter(x => x.goods_state).reduce((total,item) => {return total+=item.goods_count},0)
     },
     //已勾选商品的总价格
     checkedGoodsAmount(state) {
      return state.cart.filter(x => x.goods_state).reduce((total,item) => total += item.goods_count * item.goods_price,0).toFixed(2)
     }
   }  
}